Substrate for ink jet head with TaCr alloy protective layer, ink jet head utilizing the same and producing method therefor

ABSTRACT

For improving adhesion between a protective layer having a portion coming into contact with ink in a substrate for an ink jet head, and a resin layer thereby ensuring reliability in quality over a prolonged period, the invention provides a substrate for an ink jet head including a heat-generating resistor constituting a heat generating portion, an electrode wiring electrically connected with the heat-generating resistor and an upper protective layer provided on the heat-generating resistor and the electrode wiring across an insulating protective layer, wherein after forming an upper protective layer in which a Ta layer is laminated on a layer formed by a TaCr alloy, said Ta layer is selectively patterned and selectively removed so that the liquid flow path member is formed in a portion where the layer formed by said TaCr alloy is exposed by said removing.

TECHNICAL FIELD

The present invention relates to a substrate for an ink jet head forrecording or printing a character, a symbol or an image by discharging afunctional liquid such as ink on a recording medium including paper,plastic sheet, cloth or article, an ink jet head employing suchsubstrate and a producing method therefor.

BACKGROUND ART

A general configuration of a head employed in ink jet recording includesplural discharge ports, ink flow paths communicated with such dischargeports, and plural electrothermal converting elements for generatingthermal energy to be utilized for ink discharge. The electrothermalconverting elements are constituted by heat-generating resistors andelectrodes for supplying electric power to the heat-generatingresistors, and such electrothermal converting elements are covered by aninsulation film to secure insulation among the electrothermal convertingelements. Each ink flow path communicates, at an end opposite to thedischarge port, with a common liquid chamber which stores an inksupplied from an ink tank as an ink reservoir. The ink supplied to thecommon liquid chamber is guided to each ink flow path, and is retainedby forming a meniscus in the vicinity of the discharge port. In thisstate, the electrothermal converting element is selectively driven togenerate thermal energy, which is utilized for causing a rapid bubblingof the ink on a heat acting surface, whereby the ink is discharged by apressure resulting from such state change.

The heat acting portion of the ink jet head in such ink discharge isexposed to a high temperature generated by heating of theheat-generating resistor, and is also subjected mainly to a compositeaction of an impact of a cavitation resulting from bubble formation andcontraction of the ink, and a chemical action by the ink.

Therefore, the heat acting portion is usually provided with an upperprotective layer for protecting the electrothermal converting elementfrom such impact by cavitation and such chemical action of the ink.

Conventionally, a Ta film, relatively strong against the impact bycavitation and the chemical action of the ink, is formed with athickness of 0.2 to 0.5 μm for realizing a service life and areliability of the head at the same time.

Also in such heat acting portion, there results a phenomenon that acoloring material or an additive substance contained in the ink isdecomposed in a molecular level by heating to a high temperature to forma difficultly soluble substance which is physically adsorbed on theupper protective layer. This phenomenon is called kogation. Suchadsorption of the difficultly soluble organic or inorganic substance onthe upper protective layer causes an uneven heat conduction from theheat-generating resistor to the ink, thereby resulting in an unstablebubble generation. Therefore an excellent Ta film, relatively free fromkogation, is employed ordinarily.

In the following, a mode of generation and extinction of a bubble in theink in the heat action part will be explained with reference to FIG. 8.

In FIG. 8, a curve (a) indicates a change in time of a surfacetemperature of the upper protective layer, from a moment of applicationof a voltage to the heat-generating resistor, with a driving voltageV_(op)=1.3×V_(th) (V_(th) being a threshold voltage for bubblegeneration of the ink), a driving frequency of 6 kHz and a pulse widthof 5 μs. Also a curve (b) indicates a growth state of a bubble generatedfrom a moment of a voltage application to the heat-generating resistor.As indicated by the curve (a), a temperature rise starts from thevoltage application, then a temperature peak is reached with a certaindelay from a predetermined pulse time (because the heat from theheat-generating resistor arrives at the upper protective layer with adelay), and the temperature is lowered thereafter mainly by a heatdiffusion. On the other hand, as shown by the curve (b), a bubble startsto grow at a temperature of the upper protective layer of about 300° C.,then reaches a maximum bubble state and vanishes. In an actual head,this process is executed in a repeated manner. With a bubble generationin the ink, the surface of the upper protective layer rises for exampleto about 600° C., and this indicates how a thermal action of a hightemperature is involved in the ink jet recording.

Consequently, the upper protective layer maintained in contact with theink is required to have excellent film properties in heat resistance,mechanical properties, chemical stability, oxidation resistance, alkaliresistance etc. For the material usable for such upper protective layer,in addition to the aforementioned Ta film, there are already known aprecious metal, a high-melting transition metal, an alloy thereof, and anitride, a boride, a silicide or a carbide of such metal, or amorphoussilicon. For example, Japanese Patent Application Laid-open No.2001-105596 proposes a recording head of a long service life and a highreliability by forming an upper protective layer on a heat-generatingresistor through an insulation layer, and forming the upper protectivelayer with an amorphous alloy represented by Ta_(α)Fe_(β)Ni_(γ)Cr_(δ)(wherein 10 atomic % (at. %)≦α≦30 at. %, and α+β>80 at. %, and α<β, δ>γand α+β+γ+δ=100 at. %) in which a surface thereof in contact with theink includes an oxide of a constituent thereof.

However, a higher functionality such as a higher image quality and ahigher recording speed for an image recorded by an ink jet recordingapparatus is being required more strongly in recent years, and, in orderto meet such requirement, there are desired an improvement in inkperformance such as an improvement in color developing property andweather resistance for achieving a higher image quality and a preventionof a bleeding phenomenon (blotting between inks of different colors) inorder to achieve a higher recording speed. For this reason, it has beentried to add various components to the ink. Also types of the ink havebecome diversified, such as light-colored inks of lower density inaddition to black, yellow, magenta and cyan colors. Such inks cause acorroding phenomenon even on the Ta film, that has been consideredstable as the upper protective film, by a thermal chemical reaction withsuch inks. Such phenomenon appears conspicuously in an ink containing asalt of a divalent metal such as Ca or Mg, or a component forming achelate complex.

On the other hand, an upper protective layer with an improved corrosionresistance to the ink as explained above tends to generate a kogationmore easily since the surface is scarcely damaged because of the highercorrosion resistance, whereby a discharge speed of the ink is lowered orbecomes unstable. The kogation is generated little in the conventionalTa film presumably because the Ta film generates corrosion and kogationin a certain balanced level whereby the surface of the Ta film isabraded by such corrosion to suppress deposition of a product ofkogation.

Also for achieving a further higher recording speed in the ink jetrecording, it is necessary to further increase the drive frequencythereby executing a drive with shorter pulses. In such drive withshorter pulses, processes of heating, bubble generation, bubbleextinction and cooling are repeated within a shorter period in the heatacting portion of the head, whereby a larger thermal stress is generatedin a shorter time than in the conventional drive. Also in a drive with ashorter pulse, the cavitation impact resulting from the bubblegeneration and bubble contraction in the ink is concentrated in theupper protective film within a shorter time than in the conventionaldrive, whereby there is required an upper protective layer particularlyexcellent in the mechanical impact resistance.

For forming an ink jet head with an ink jet head substrate provided withsuch upper protective layer, there is employed, as disclosed in JapanesePatent Application Laid-open No. H6-286149, a method of forming an inkflow path with a soluble resin by a photolithographic patterning, thencovering and hardening such pattern with an epoxy resin or the like, andeliminating such soluble resin after the substrate is cut into a piece.

It is also possible, as disclosed in Japanese Patent ApplicationLaid-open No. 2002-113870, to achieve a higher durability and a higherreliability by constituting the upper protective layer with two layers,employing an amorphous Ta film of a high ink corrosion resistance as alower layer and a Ta film of relatively low generation of kogation as anupper layer.

However, in case of elongating an ink discharge element (to 0.5 inchesor larger) for achieving a higher recording speed or in case ofemploying diversified inks containing additives for improving a lightfastness or a gas resistance of the inks on a recording medium, thereare generated strains by a difference in the linear expansioncoefficient of such components, and by a stress in the resin layerconstituting walls of the liquid flow path or the discharge port, and aninfluence on the interface by inks of new types, thus leading to apeeling phenomenon between the covering resin layer constituting thewalls of the liquid flow path or the discharge port and the upperprotective layer on the heater substrate. Also, even in case an organicadhesion promoting layer is provided on the upper protective layer,there may result a peeling at the interface between the organic adhesionpromoting layer and the upper protective layer to cause a penetration ofthe ink onto the substrate and to induce a corrosion of the wirings,thereby hindering satisfactory recording or reliability in quality overa prolonged period.

DISCLOSURE OF THE INVENTION

An object of the present invention is to improve adhesion between anupper protective layer of a substrate for an ink jet head, having aportion coming into contact with an ink, and a resin layer, therebyproviding an ink jet head and a substrate therefor capable of ensuringreliability over a prolonged period.

Another object of the present invention is to provide a substrate for anink jet head with an improved adhesion between an upper protective layerand resin layer even in case of a smaller dot for a higher definition ofa recorded image or of a longer recording element for a higher recordingspeed or in case of employing diversified inks thereby enabling a higherdensity of the head, an ink jet head provided with such substrate, and aproducing method thereof.

Another object of the present invention is to provide a configuration ofan upper protective layer realizing a high durability and a highreliability even for highly corrosive inks, thereby providing asubstrate for an ink jet head and an ink jet head of a long service lifeand a producing method thereof.

Another object of the present invention is to provide a substrate forink jet comprising a base plate formed with a heat-generating resistorfor generating energy for discharging ink, an electrode wiringelectrically connected with said heat-generating resistor, and an upperprotective layer provided above said heat-generating resistor and saidelectrode wiring, and comprising a TaCr alloy, wherein said upperprotective layer is formed with a construction made by resin on an upperportion thereof and said resin construction is fixed on said upperprotective layer.

Another object of the present invention is to provide an ink jet headcomprising, a discharge port for discharging a liquid, a liquid flowpath communicating with said discharge port and having a portion forapplying thermal energy for discharging said liquid to said liquid, aheat-generating resistor for generating said thermal energy, anelectrode wiring electrically connected with said heat-generatingresistor, and an upper protective layer provided above saidheat-generating resistor and said electrode wiring, and comprising aTaCr alloy, wherein said upper protective layer is formed with aconstruction made by resin on an upper portion thereof and said resinconstruction is fixed on said upper protective layer:

Another object of the present invention is to provide a producing methodfor an ink jet head including, on a substrate, a heat-generatingresistor constituting a heat generating portion, an electrode wiringelectrically connected with said heat-generating resistor, an upperprotective layer provided on said heat-generating resistor and saidelectrode wiring and having a contact surface with an ink, and a liquidflow path member formed by a resin layer on said substrate, comprising,a step of forming an upper protective layer in which a Ta layer islaminated on a layer formed by a TaCr alloy, a step of selectivelypatterning said Ta layer and selectively removing said Ta layer, a stepof forming the liquid flow path member in a portion where the layerformed by said TaCr alloy is exposed by said removing step.

Another object of the present invention is to provide a substrate for anink jet head, having an excellent adhesion between an upper protectivelayer and a resin layer and enabling to form a pattern of a liquid flowpath with a high precision thereby providing an ink jet head of a highreliability, also not causing a peeling of a member constituting aliquid flow path even in an ink jet head elongated to 0.5 inches orlarger thereby ensuring a high reliability over a prolonged period, anink jet head and a producing method thereof.

Another object of the present invention is to provide a substrate for anink jet head enabling to form a pattern of a liquid flow path with ahigh precision by an excellent adhesion between an upper protectivelayer and a member constituting the liquid flow path, thereby ensuring ahigh reliability even in case of a smaller dot formation for achieving ahigher definition in a recorded image or of a high-speed drive forachieving a high-speed recording, an ink jet head and a producing methodthereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial cross-sectional view of a substrate for ink jet headof the present invention;

FIGS. 2A, 2B, 2C and 2D are views showing a method for forming adischarge element on the substrate for ink jet head of the presentinvention;

FIGS. 3A, 3B, 3C, 3D and 3E are views showing another method for forminga discharge element on the substrate for ink jet head of the presentinvention;

FIG. 4 is a view showing a film forming apparatus for forming layers ofthe substrate for ink jet head of the present invention;

FIG. 5 is a schematic view showing a configuration of an ink jetrecording apparatus in which the ink jet head of the present inventionis applied;

FIG. 6 is a partial plan view of another embodiment for forming adischarge element on the substrate for ink jet head of the presentinvention;

FIG. 7 is a schematic partial cross-sectional view of FIG. 6; and

FIG. 8 is a chart showing a temperature change in an upper protectivelayer and a bubble generation state after a voltage application.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a schematic partial cross-sectional view showing an ink jethead in which a configuration of the present invention is applicable.

In FIG. 1, there are shown a silicon substrate 101, a heat accumulatinglayer 102 constituted of a thermal oxidation film, an interlayer film103 constituted for example of an SiO film or an SiN film and alsoserving for heat accumulation, a heat-generating resistor layer 104, ametal wiring layer 105 constituted of a metal material such as Al, Al—Sior Al—Cu, a protective layer 106 constituted for example of an SiO filmor an SiN film and also serving as an insulation film, an upperprotective layer 107 provided on the protective layer 106 for protectingan electrothermal converting element from a chemical or physical impactassociated with a heat generation of the heat-generating resistor, and aheat acting portion 108 in which a heat generated by a heat-generatingresistor of the heat-generating resistor layer 104 is transmitted toink.

The heat acting portion of the ink jet head is exposed to a hightemperature resulting from heat generation by the heat-generatingresistor, and is also principally subjected to a cavitation impactresulting from a bubble generation in the ink and a bubble contractionthereafter and a chemical action by the ink. For this reason, the upperprotective layer 107 is provided on the thermal action portion in orderto protect the electrothermal converting element from such cavitationimpact and chemical action of the ink. On the upper protective layer107, there is formed a discharge element including a discharge port 110,utilizing a member 109 for forming a flow path.

FIGS. 2A to 2D show a method for forming a discharge element.

On an ink jet head substrate 200, which is same as the ink jet headsubstrate 100 shown in FIG. 1, a resist material is coated by a spincoating method, as a soluble solid layer 201 for finally constituting anink flow path. The resist material, constituted of polymethylisopropenylketone, functions as a negative-working resist and is patterned into aform of an ink flow path by a photolithographic method. Then a coveringresin layer 203 is formed in order to form a wall of the ink flow pathand a discharge port. Prior to forming the covering resin layer 203, asilane coupling process or the like may be suitably applied in order toimprove adhesion. The covering resin layer 203 can be coated on the inkjet head substrate 200 bearing the pattern of the ink flow path, bysuitably selecting an already known coating method. Then an ink supplyaperture 206 is formed from a rear surface of the ink jet head substrate200 by anisotropic etching, sand blasting or anisotropic plasma etching.The ink supply aperture 206 can be formed most preferably by chemicalanisotropic etching of silicon utilizing tetrramethylhydroxylamine(TMAH), NaOH or KOH. Then, for eliminating the soluble solid layer 201,there are executed a flush exposure with a deep UV light, a developmentand a drying.

It is also possible, as shown in FIGS. 3A to 3E, after formation of anupper protective film 107 (Ta_(100-x)Cr_(x) film), to form an organicadhesion promoting film 307 under the nozzle constituting member. As theorganic adhesion promoting film 307, a polyether amide resin wasselected. Such resin is particularly preferably because of an excellentresistance to alkali etching, a satisfactory adhesion to an organic filmsuch as of silicon and an advantage of being usable as an ink-resistantprotective film of the ink jet recording head. Thereafter aphotolithographic process is applied to form a pattern as shown in FIGS.3A to 3E. Such patterning can be achieved by a method similar to a dryetching of an ordinary organic film. More specifically, it can beachieved by an etching with oxygen gas plasma, utilizing apositive-working resist as a mask.

In the following, there will be explained, with reference to FIGS. 3A to3E, a method of forming the organic adhesion promoting film 307 afterthe formation of the upper protective film 107 (Ta_(100-x)Cr_(x) film).On an ink jet head substrate 300, a resist material is coated by a spincoating method to form a soluble solid layer 301 for finallyconstituting an ink flow path. The resist material, constituted ofpolymethylisopropenyl ketone, functions as a negative-working resist andis patterned into a form of an ink flow path by a photolithographicmethod.

Then a covering resin layer 303 is formed in order to form a wall of theink flow path and a discharge port. Prior to forming the covering resinlayer 303, a silane coupling process or the like may be suitably appliedin order to improve adhesion. The covering resin layer 303 can be coatedon a substrate for ink jet, on which the pattern of the ink flow path isformed, by suitably selecting an already known coating method. Thecoated covering resin layer 303 is patterned by a photolithographicprocess. Then an ink supply aperture 306 is formed from a rear surfaceof the substrate by anisotropic etching, sand blasting or anisotropicplasma etching. The ink supply aperture 206 is formed most preferably bychemical anisotropic etching of silicon utilizingtetrramethylhydroxylamine (TMAH), NaOH or KOH. Then, for eliminating thesoluble solid layer 301, there are executed a flush exposure with a deepUV light, a development and a drying.

The substrate, bearing the nozzle portion formed through the stepsexplained in FIGS. 2A to 2D and 3A to 3E, is cut and separated with adicing saw or the like into a chip, which is subjected to an electricalconnection for driving the heat-generating resistor and an adjoining ofan ink supply member, thereby completing an ink jet head.

The upper protective layer coming into contact with the ink, is requiredto have excellent film characteristics such as a heat resistance,mechanical properties, a chemical stability, an oxidation resistance andan alkali resistance, and an excellent adhesion to the organic adhesionpromoting layer and the nozzle-constituting member, and is constitutedof Ta and Cr. It is preferably constituted of Ta_(100-x)Cr_(x) in whichx≧12 at. %.

A thickness of the upper protective layer 107 is selected within a rangeof 50 to 500 nm, preferably 100 to 300 nm. Also the upper protectivelayer has at least a compression stress, preferably not exceeding1.0×10¹⁰ dyn/cm². The upper protective layer 107 can be formed byvarious methods, but can generally be formed by a magnetron sputteringmethod utilizing a high frequency (RF) power source or a direct current(DC) power source.

FIG. 4 schematically shows a sputtering apparatus employed for formingthe upper protective layer 107. In FIG. 4, there are shown a Ta targetand a Cr target 4001, a flat magnet 4002, a shutter 4011 for controllingfilm formation on a substrate, a substrate holder 4003, a substrate4004, and a power supply connected to the target 4001 and the substrateholder 4003. In FIG. 4, there is also shown an external heater 4008provided around an external peripheral wall of a film forming chamber4009. The external heater 4008 is used for regulating a temperature ofan atmosphere in the film forming chamber 4009. At the rear of thesubstrate holder 4003, an internal heater 4005 is provided forregulating the temperature of the substrate. The temperature control ofthe substrate is preferably achieved in combination with the externalheater 4008.

A film formation with the apparatus shown in FIG. 4 is executed in afollowing manner. At first the film forming chamber 4009 is evacuated bya vacuum pump 4007 to 1×10⁻⁵ to 1×10⁻⁶ Pa. Then Ar gas is introducedthrough a mass flow controller (not shown), into the film formingchamber 4009 via a gas introducing aperture 4010. In this operation, theinternal heater 4005 and the external heater 4008 are so regulated thatthe substrate and the atmosphere become predetermined temperatures. Thenan electric power is applied from the power supply 4006 to the target4001 to cause a sputtering discharge, and the shutter 4011 is adjustedto form a thin film on the substrate 4004.

In the present invention, the film formation can be executed by a binarysimultaneous sputtering utilizing a Ta target and a Cr target andapplying electric powers thereto from two power sources respectivelyconnected thereto. In such case, it is possible to independentlyregulate the electric power applied to each target. It is also possibleto obtain a film of a desired composition by preparing plural alloytargets adjusted in advance to desired compositions and to executesputtering with a single target or simultaneously with plural targets.

At the formation of the upper protective layer 107, a strong filmadhesion can be obtained by heating the substrate to 100 to 300° C. asexplained above. Also a strong film adhesion can be achieved by a filmformation with a sputtering method capable of forming particles of arelatively high kinetic energy as explained in the foregoing.

Also a strong film adhesion can be obtained by providing the film atleast with a compression stress, not exceeding 1.0×10¹⁰ dyn/cm². Suchfilm stress can be regulated by suitably setting a flow rate of the Argas introduced into the film forming apparatus, a power applied to thetarget and a heating temperature of the substrate.

FIG. 5 is an external view of an ink jet apparatus in which the presentinvention is applicable. This ink jet apparatus is of an old type, butthe present invention is more effective when applied to an ink jetapparatus of a latest type.

In the ink jet apparatus shown in FIG. 5, a recording head 2200 ismounted on a carriage 2120 engaging with a spiral groove 2121 of a leadscrew 2104 which is rotated through power transmission gears 2102, 2103in linkage with a forward or reverse rotation of a driving motor 2101,and is reciprocated together with the carriage 2120 in directions a, balong a guide 2119, by the power of the driving motor 2101. A paperpressing plate 2105, for recording paper P conveyed on a platen 2106 byan unrepresented recording medium supplying apparatus, presses therecording paper to the platen 2106 along the moving direction of thecarriage 2120.

Photocouplers 2107, 2108 constitute home position detecting means, forconfirming presence of a lever 2109 of the carriage 2120 in the positionof the photocouplers thereby switching the rotating direction of thedriving motor 2101. There are also provided a member 2110 for supportinga cap member 2111 for capping an entire face of the recording head 2200,and suction means 2112 for suction removal of ink in the cap member 2111thereby achieving a suction recovery of the recording head 2200 throughan aperture 2113 in the cap. A cleaning blade 2114 and a movable member2115 for supporting the cleaning blade in movable manner in front-reardirection are supported by a support plate 2116 in a main body of theapparatus. The cleaning blade 2114 is not limited to the illustratedform and any known cleaning blade can naturally be applicable.

A lever 2117 for starting a suction of a suction recovery operation ismoved by a movement of a cam 2118 engaging with the carriage 2120,thereby controlling the driving power of the driving motor 2101 throughtransmission means such as a clutch. A recording control unit (notshown) for supplying a signal to a heat generating unit 2110 provided inthe recording head 2200 and for controlling the function of theaforementioned mechanisms is provided in the main body of the recordingapparatus.

The ink jet recording apparatus 2100 of the above-explainedconfiguration executes a recording by a reciprocating motion of therecording head 2200 over an entire width of the recording paper Pconveyed onto the platen 2106 by the recording medium supplyingapparatus, and is capable of a high-speed recording of a high precision,as the recording head 2200 is prepared by a method explained in theforegoing.

In the following, the present invention will be clarified further byexamples of formation of the upper protective layer 107 and of an inkjet head utilizing the same. However, the present invention is notlimited by such examples.

The apparatus shown in FIG. 4 and the aforementioned film forming methodwere employed in forming a Ta—Cr film for the upper protective layer 107on a silicon wafer, and properties of such film were evaluated. The filmforming operations and the evaluation of the film properties areexplained in the following. It is to be noted that an unintended element(contamination) contained in a completed film through the film formingprocess etc. is not included in the present invention.

[Film Forming Operation]

At first a thermal oxide film was formed on a monocrystalline siliconwafer, and such silicon wafer (substrate 4004) was placed on thesubstrate holder 4003 in the film forming chamber 4009 of the apparatusshown in FIG. 4. Then the interior of the film forming chamber wasevacuated by the vacuum pump 4007 to 8×10⁻⁶ Pa. Then, Ar gas wasintroduced from the gas introducing aperture 4010 into the film formingchamber 4009 and the interior thereof was adjusted to followingconditions:

[Film Forming Condition]

-   -   substrate temperature: 200° C.    -   gas atmosphere temperature in film forming chamber: 200° C.    -   gas mixture pressure in film forming chamber: 0.6 Pa

Then, by a binary sputtering method utilizing a Ta target and a Crtarget with a variable power to each target, a Ta_(100-x)Cr_(x) film wasformed with a thickness of 200 nm on the thermal oxide film of thesilicon wafer, thereby obtaining samples 1 to 7.

[Evaluation of Film Properties]

A composition analysis was conducted on each of the obtained samples 1to 7 by a Rutherford back scattering (RBS). Obtained results are shownin Table 1. As shown in Table 1, films of different compositions can beobtained by changing the powers supplied to the Ta and Cr targets.

TABLE 1 Power [W] Film composition Sample No. Ta Cr [at. %] 1 720 100Ta₈₈Cr₁₂ 2 680 100 Ta₈₆Cr₁₄ 3 640 100 Ta₈₂Cr₁₈ 4 600 100 Ta₈₀Cr₂₀ 5 500150 Ta₇₀Cr₃₀ 6 500 400 Ta₄₅Cr₅₅ 7 500 600 Ta₂₇Cr₇₃

[Film Stress]

Then a film stress of each sample was measured from an amount ofdeformation of the substrate before and after the film formation. As aresult, with an increase in the Cr concentration in the Ta_(100-x)Cr_(x)film, the film stress tended to change from a compression stress to atensile stress and a film adhesion tended to decrease. A strong filmadhesion can be obtained by forming a film stress at least as acompression stress and not exceeding 1.0×10¹⁰ dyn/cm².

[Adhesion with Resin]

EXAMPLE 1

In order to simply evaluate an adhesion between a Ta₈₈Cr₁₂ film 107(representing a film with a composition ratio of Ta 88 at. % and Cr 12at. %; hereinafter composition being represented in a similar manner) ofthe present example and an organic adhesion promoting film (polyetheramide resin) 307, a tape peeling test was conducted after a pressurecooker test (PCT).

The tape peeling test was conducted in the following manner. On asilicon wafer bearing the upper protective layer 107, an organicadhesion promoting film (polyether amide resin) 307 was formed with athickness of 2 μm, and squares of 1×1 mm in a checkerboard pattern of 10(longitudinal)×10 (lateral)=100 squares were formed with a cutter knifeon the organic adhesion promoting film 307. Then a PCT was conducted byimmersion in an alkaline ink under conditions of 121° C. and 2.0265×10⁵Pa (2 atm.) for 10 hours. Thereafter, an adhesive tape was applied onthe squares in the checkerboard pattern and peeled, and a number ofsquares peeled by the adhesive tape among 100 squares was investigated.As a result, a generally satisfactory result was obtained, thoughpeeling was observed in about 15 squares among 100 (Table 2).

COMPARATIVE EXAMPLE 1

A method similar to that in Example 1 was employed to evaluate anadhesion between the Ta film and the organic adhesion promoting film(polyether amide resin) 307 after PCT, and the obtained result is shownin Table 2.

As shown in Table 2, a peeling was generated at the interface betweenthe Ta film and the organic adhesion promoting film 307 after the PCT,clearing indicating a deterioration of the adhesion property.

EXAMPLES 2 TO 7

A method similar to that in Example 1 was employed to evaluate anadhesion of Ta_(100-x)Cr_(x) films of different compositions after PCT,and the obtained results are shown in Table 2.

COMPARATIVE EXAMPLES 2 AND 3

A method similar to that in Example 1 was employed to evaluate anadhesion after PCT. Evaluations were made on Ta₂₀Fe₆₁Cr₁₄Ni₅(Comparative Example 2) and Ta₈₇Fe₁₀Cr₂Ni₁ (Comparative Example 3), andthe obtained results are shown in Table 2.

As will be apparent from these results, the Ta₂₀Fe₆₁Cr₁₄Ni₅ film andTa₈₇Fe₁₀Cr₂Ni₁ film, conventionally employed as the upper protectivefilm, could not provide a sufficient adhesion property because of thepeeling at the interface between the upper protective layer 107 and theorganic adhesion promoting film 307.

TABLE 2 Film Number of Film composition thickness peelings [at. %] [nm](after PCT) Ex. 1 Ta₈₈Cr₁₂ 200 15/100  Ex. 2 Ta₈₆Cr₁₄ 200 8/100 Ex. 3Ta₈₂Cr₁₈ 200 0/100 Ex. 4 Ta₈₀Cr₂₀ 200 0/100 Ex. 5 Ta₇₀Cr₃₀ 200 0/100 Ex.6 Ta₄₅Cr₅₅ 200 0/100 Ex. 7 Ta₂₇Cr₇₃ 200 0/100 Comp. Ex. 1 Ta 200100/100  Comp. Ex. 2 Ta₂₀Fe₆₁Cr₁₄Ni₅ 200 66/100  Comp. Ex. 3Ta₈₇Fe₁₀Cr₂Ni₁ 200 100/100 

As explained in the foregoing, the adhesion between the upper protectivelayer 107 and the organic adhesion promoting layer 307 after the PCT, inthe Ta_(100-x)Cr_(x) film, tended to become lower in a film with a lowCr content, and was within a satisfactory range in case X was equal toor higher than 12 at. %.

In addition to the aforementioned results in the presence of an adhesionpromoting layer, similar results were obtained in the absence of theadhesion promoting layer, and it was identified that a Ta_(100-x)Cr_(x)film (X≧12 at. %) was effective for the adhesion regardless of thepresence or absence of the adhesion promoting layer.

[Evaluation of Ink Jet Properties]

EXAMPLE 8

In the present example, a Si substrate or a Si substrate in which adriving IC is formed is used for a sample for evaluating the ink jetproperties. In case of a Si substrate, an SiO₂ heat accumulation layer102 (FIG. 1) of a thickness of 1.8 μm is formed by thermal oxidation,sputtering or CVD, and, a Si substrate already having an IC is alsosubjected to a formation of an SiO₂ heat accumulation layer in apreparation process.

Then an SiO₂ interlayer insulation film 103 of a thickness of 1.2 μm wasformed by sputtering or CVD. Then a Ta₄₀Si₂₁N₃₉ heat-generating resistorlayer 104 of a thickness of 50 nm was formed by reactive sputteringemploying a Ta—Si target. This operation was conducted at a substratetemperature of 200° C. Then an Al film for the metal wiring 105 wasformed with a thickness of 200 nm by sputtering.

Then a patterning was executed by a photolithographic process to form aheat acting portion 108 of 26×26 μm in which the Al film was eliminated.Then an SiN insulating member of a thickness of 300 nm as a protectivefilm 106 by plasma CVD.

Then, as an upper protective layer 107, a Ta₈₈Cr₁₂ film was formed witha thickness of 200 nm by sputtering under varying powers to a Ta targetand a Cr target.

Then the upper protective layer 107 was patterned by dry etching.

Subsequently, in order to improve adhesion between the upper protectivelayer and a nozzle-constituting member, an organic adhesion promotingfilm (polyether amide resin) 307 was formed with a thickness of 2 μm,whereby an ink jet head substrate was obtained.

Such ink jet head substrate was employed in a producing method shown inFIG. 3 to prepare an ink jet head, which was subjected to a dischargedurability test in an ink jet recording apparatus. The test wasconducted with a driving frequency of 15 kHz and a pulse width of 1.0μsec, and an abrasion of the upper protective layer 107 after 1.0×10⁸pulses was evaluated by a cross sectional observation by FIB. Thedriving voltage was 1.3×V_(th), in which V_(th) is a bubble generationthreshold voltage for ink discharge. Also there was employed an inkincluding a nitrate group-containing divalent metal salt Ca(NO₃)₂.4H₂Oby about 4%.

As shown in Table 3, it was identified that, despite of a slightabrasion after continuous discharge up to 2.0×10⁸ pulses, the upperprotective layer was stable with stable discharge characteristics.

COMPARATIVE EXAMPLE 4

An ink jet head was prepared in the same manner as in Example 8, exceptthat the upper protective layer 107 was prepared with a Ta film. Suchink jet head was subjected to a discharge durability test as in Example1, and an obtained result is shown in Table 3. As shown in Table 3, thedischarge became impossible before reaching 2.0×10⁸ pulses inComparative Example 4. An analysis conducted by disassembling the inkjet head proved that the corrosion reached the heat-generating resistorlayer and caused a breakage thereof.

EXAMPLES 9 TO 16

Ink jet heads were prepared in the same manner as in Example 8, exceptthat the upper protective layers 107 were prepared with compositions andthicknesses as shown in Table 3. Such ink jet heads were subjected to adischarge durability test as in Example 8, and obtained results areshown in Table 3.

COMPARATIVE EXAMPLES 5 AND 6

Ink jet heads were prepared in the same manner as in Example 8, exceptthat the upper protective layers 107 were prepared with compositions andthicknesses as shown in Table 3.

Such ink jet heads were subjected to a discharge durability test as inExample 8, and obtained results are shown in Table 3.

As shown in Table 3, Ta₂₀Fe₆₁Cr₁₄Ni₅ (Comparative Example 5) showedscarce abrasion and was stable in the discharge durability test.

Ta₈₇Fe₁₀Cr₂Ni₁ (Comparative Example 6) showed a abrasion to about a halfof the film thickness.

These results indicate followings.

As will be apparent from the results shown in Table 3, the stability ofthe upper protective layer 107 in the discharge durability test againstabrasion is dependent on the composition of Ta_(100-x)Cr_(x) film, andbecomes superior as the Cr content increases. More specifically, theupper protective layer 107 is extremely stable against abrasion in caseX≧12 at. % in the composition of the Ta_(100-x)Cr_(x) film.

Also the upper protective film 107 preferably has a film thickness of100 to 500 nm. A film thickness less than 100 nm may result in aninsufficient protective ability against ink, while a film thicknessexceeding 500 nm may hinder an efficient energy conduction from theheat-generating resistor layer to the ink, thus resulting in a largeenergy loss.

In these examples, it was possible to obtain excellent durability evenwith a film thickness of about 100 nm. As regards the film stress, atleast a compression stress, not exceeding 1.0×10¹⁰ dyn/cm² could providea strong film adhesive force with an excellent durability.

As explained in the foregoing examples, it is rendered possible, byconstituting the upper protective layer 107 with an alloy of Ta and Cr,by forming a resin (flow path-forming member 109) on the upperprotective layer 107 and by fixing such resin on the upper protectivelayer 107, to provide an ink jet head substrate enabling to realize ahigher density, an ink jet head provided with such substrate, and an inkjet apparatus equipped with such ink jet head.

TABLE 3 Film Film Abrasion in discharge composition thickness durabilitytest (after Example [at. %] [nm] 2.0 × 10⁸ pulses) Ex. 8 Ta₈₈Cr₁₂ 200 ±Ex. 9 Ta₈₆Cr₁₄ 200 + Ex. 10 Ta₈₂Cr₁₈ 200 + Ex. 11 Ta₈₀Cr₂₀ 200 + Ex. 12Ta₈₀Cr₂₀ 100 + Ex. 13 Ta₈₀Cr₂₀ 400 + Ex. 14 Ta₇₀Cr₃₀ 200 + Ex. 15Ta₄₅Cr₅₅ 200 + Ex. 16 Ta₂₇Cr₇₃ 200 + Comp. Ex. 4 Ta 200 − Comp. Ex. 5Ta₂₀Fe₆₁Cr₁₄Ni₅ 200 + Comp. Ex. 6 Ta₈₇Fe₁₀Cr₂Ni₁ 200 ±

EXAMPLE 17

In the present example, the upper protective layer 107 has a two-layeredconfiguration, and, in the heat acting portion, there is employed atwo-layered configuration constituted of an upper Ta layer 111 and alower TaCr layer 112 while, under the flow path forming member 109,there is employed a one-layered configuration of the lower layer 112only.

More specifically there is shown a case of employing a Ta₈₀Cr₂₀ film asthe lower film 112 of the upper protective film 107 and a Ta film as theupper film 111.

The lower film 112 was formed by a binary sputtering utilizing a Tatarget and a Cr target, with a composition of Ta₈₀Cr₂₀ and a thicknessof 130 nm on the insulation layer. Conditions of binary sputtering weredetermined by analyzing the composition in advance by changing powersfor Ta sputtering and for Cr sputtering. Also instead of binarysputtering, there may be executed a sputtering with a TaCr alloy targetof a composition known in advance.

Thereafter the upper layer 111 was formed with a thickness of 100 nm bysputtering utilizing a Ta target. The film formation was executed incontinuous manner in the same sputtering chamber.

Thereafter the Ta film constituting the upper layer 111 was patterned byan ordinary photolithographic process by steps of resist patterning(resist coating, exposure and development), Ta etching and resiststripping.

In this operation, the pattern of the Ta film can be arbitrarilyselected by a photomask pattern at the exposure step. Therefore, thepattern was so selected as to form a Ta film on the heat generating part(heat acting portion 108) but not to form Ta film as the upper layer 111where the liquid flow path forming member 109 is to be formed, as shownin FIGS. 6 and 7. Then the TaCr film was patterned by aphotolithographic process by steps of resist patterning (resist coating,exposure and development), Ta etching and resist stripping. In FIG. 6,there are shown a low path member forming portion 1090 including, in apartial area, a configuration in which the flow path member 109 islaminated on the organic adhesion promoting layer 307, an upper layerpattern 1110 of the upper protective layer, a lower layer pattern 1120of the upper protective layer, a heat generating resistor 1080, and anelectrode wiring 1050.

The etching of the TaCr film was conducted with a dry etching apparatus,selecting an etching gas, a gas pressure and a power capable ofachieving a selective etching ratio with the underlying insulatingprotective layer. In the formation of the pattern of the TaCr film, itwas formed under the portion 1090 for forming the liquid flow pathforming member as shown in FIG. 6.

Also as shown in FIG. 7 in a cross section, on the Ta₈₀Cr₂₀ film of athickness of 230 nm constituting the lower layer film 112 of the upperprotective layer 107, there were laminated an organic adhesion promotingfilm 307 constituting a lower liquid flow path member and a liquid flowpath member 109 in this order, and the adhesion between the Ta₈₀Cr₂₀film, and the organic adhesion promoting film 307 and the liquid flowpath member 109 thereon in a simple manner. The evaluation was made byexecuting a tape peeling test in an initial state and after a pressurecooler test (PCT). The organic adhesion promoting film 307 as the lowerliquid flow path member was employed in this example for the purpose offurther improving the adhesion between the liquid flow path member 109and the TaCr film.

The PCT was conducted by immersion in an alkaline ink under conditionsof 121° C. and 2.0265×10⁵ Pa. (2 atm.) for 10 hours. Obtained resultsare shown in Table 4. These results indicate that the Ta₈₀Cr₂₀ film hada satisfactory adhesion.

TABLE 4 Film Upper thick- Films Adhesion Tape protective ness formedAdhesion (after peeling layer [nm] above (initial) PCT) test Ex. 17 TaCr230 organic + + + adhesion promoting layer/flow path member Comp. Ta 230organic + − ± Ex. 7 adhesion promoting layer/flow path member

After the patterning of the Ta₈₀Cr₂₀ film constituting the lower layer112 of the upper protective layer 107 and the Ta film constituting theupper layer 111, a soluble solid layer 301 was coated by a spin coatingmethod on the substrate, and was exposed to form a shape to constitutean ink flow path. The shape of the ink flow path could be obtained withan ordinary mask and a deep UV light. Then a covering resin layer 303was laminated, then exposed with an exposure apparatus and was developedto form a discharge port 110. Subsequently, after formation of an inksupply aperture 306 by an anisotropic etching of silicon with TMAH, aportion to be dissolved of the covering resin layer 303 was eliminatedby a flush exposure to a deep UV light, a development and a drying. Thesubstrate, bearing the nozzle portion formed through the steps explainedin the foregoing, is cut and separated with a dicing saw or the likeinto a chip, which is subjected to an electrical connection for drivingthe heat-generating resistor and an adjoining of an ink supply member,thereby completing an ink jet head.

Thus prepared ink jet head provided a satisfactory recording quality inan evaluation of discharging an alkaline ink of pH 10. Also in case thisink jet head, after immersion in this ink for 3 months at 60° C.,provided a satisfactory recording quality in an ink dischargingevaluation, and did not show a peeling of the covering resin layer 303.

COMPARATIVE EXAMPLE 7

There is shown a case of employing a single-layered film of Ta only asthe upper protective layer.

In the present comparative example, a Ta film of a thickness of 230 nmwas formed by sputtering with a Ta target.

Thereafter the Ta film was patterned by an ordinary photolithographicprocess by steps of resist patterning (resist coating, exposure anddevelopment), Ta etching and resist stripping.

In this operation, the pattern of the Ta film can be arbitrarilyselected by a photomask pattern at the exposure step.

In order to simply evaluate the adhesion between the Ta film of athickness of 230 nm, and the liquid flow path member 109 and the organicadhesion promoting film 307 constituting the lower liquid flow pathmember, there was executed a tape peeling test. The evaluation was madeby executing the tape peeling test in an initial state and after apressure cooler test (PCT).

The PCT was conducted by immersion in an alkaline ink under conditionsof 121° C. and 2.0265×10⁵ Pa (2 atm.) for 10 hours. Obtained results areshown in Table 4.

Based on these results, in which the Ta film showed a peeling after thePCT, it was confirmed that the adhesion was superior in theconfiguration of the foregoing Example 17 employing Ta₈₀Cr₂₀ as thelower film 112 of the upper protective layer 107 and a Ta film as theupper layer film 111.

Thereafter, a soluble solid layer 301 was coated by a spin coatingmethod on the substrate bearing the upper protective layer 107, and wasexposed to form a shape to constitute an ink flow path. The shape of theink flow path could be obtained with an ordinary mask and a deep UVlight. Then a covering resin layer 303 was laminated, then exposed withan exposure apparatus and was developed to form a discharge port 110.Subsequently, after formation of an ink supply aperture 306 by ananisotropic etching of silicon with TMAH, a portion to be dissolved ofthe covering resin layer 303 was eliminated by a flush exposure to adeep UV light, a development and a drying. The substrate, bearing thenozzle portion formed through the steps explained in the foregoing, iscut and separated with a dicing saw or the like into a chip, which issubjected to an electrical connection for driving the heat-generatingresistor and an adjoining of an ink supply member, thereby completing anink jet head.

Thus prepared ink jet head provided a satisfactory recording quality inan evaluation of discharging an alkaline ink of pH 10. However, this inkjet head, when immersed in this ink for 3 months at 60° C., showed aportion of non-discharge and could not provide a satisfactory recordingquality. In an observation of the ink jet head, a peeling of thecovering resin layer 303 was observed and there was confirmed aconnected state of the ink flow paths.

In this example, it is rendered possible, by forming a TaCr film in alower layer, coming into contact with the liquid flow path member, ofthe upper protective film on the heater substrate, and by forming a Tafilm in an upper layer coming into contact with the ink, to improve theadhesion between the upper protective layer and the resin layerconstituting the liquid flow path even in case of a smaller dot forachieving a higher definition in the recorded image or of an elongatedhead for achieving a higher recording speed, or in case of employingdiversified inks, thereby providing an ink jet head substrate and an inkjet head enabling to realize a higher density, and an ink jet apparatusequipped with such ink jet head.

Also a two-layered configuration of the upper protective layer realizesa high durability and a high reliability for diversified inks such as anink showing a high discharge instability by kogation and an ink with ahigh corrosive property, thereby providing an ink jet head substrate andan ink jet head of a long service life, and an ink jet apparatusequipped with such ink jet head.

In the foregoing examples, there has been explained an ink jet recordinghead of which discharge elements such as a discharge port and an inkflow path are prepared by a photolithographic technology, but thepresent invention also includes a configuration in which an orificeplate constituting a discharge port or a top plate constituting an inkflow path is separately formed and adhered, for example, with anadhesive material, onto the upper protective layer.

1. A substrate for an ink jet head comprising: a base plate formed with a heat-generating resistor for generating energy for discharging ink; an electrode wiring electrically connected with said heat-generating resistor; and a protective layer provided above said heat-generating resistor and said electrode wiring, said protective layer being constituted of a two-layered section formed by a lower layer of a TaCr alloy and an upper layer of Ta, and of a single-layered section having said lower layer, wherein a resin construction made by resin is formed on said lower layer of said single-layered section and said upper layer of said two-layered section is provided at a position in contact with ink at least above said heat-generating resistor.
 2. The substrate according to claim 1, wherein said lower layer of said single-layered section fixes a flow path forming member as resin construction through an organic adhesion promoting layer.
 3. The substrate according to claim 1, wherein said lower layer of said protective layer contains Cr in an amount equal to or higher than 12 atomic %.
 4. The substrate according to claim 1, wherein said lower layer of said protective layer has an amorphous structure.
 5. The substrate according to claim 1, wherein said lower layer of said protective layer has a thickness within a range of 50 to 500 nm.
 6. The substrate according to claim 1, wherein said lower layer of said protective layer has a film stress which is at least a compression stress and is equal to or less than 1.0×10¹⁰ dyn/cm².
 7. A substrate for an ink jet head comprising: a base plate formed with a heat-generating resistor for generating energy for discharging ink; an electrode wiring electrically connected with said heat-generating resistor; and a protective layer provided above said heat-generating resistor and said electrode wiring, and constituted of a TaCr alloy containing Cr in an amount equal to or higher than 12 atomic %, a construction made by resin being formed on said protective layer.
 8. The substrate according to claim 7, wherein said protective layer fixes a flow path forming member as resin construction through an organic adhesion promoting layer.
 9. The substrate according to claim 7, wherein said protective layer has an amorphous structure.
 10. The substrate according to claim 7, wherein said protective layer has a thickness within a range of 50 to 500 nm.
 11. The substrate according to claim 7, wherein said protective layer has a film stress which is at least a compression stress and is equal to or less than 1.0×10¹⁰ dyn/cm².
 12. A substrate for an ink jet head comprising: a base plate formed with a heat-generating resistor for generating energy for discharging ink; an electrode wiring electrically connected with said heat-generating resistor; and a protective layer provided above said heat-generating resistor and said electrode wiring, and having a film stress which is at least a compression stress and is equal to or less than 1.0×10¹⁰ dyn/cm², a construction made by resin being formed on said protective layer.
 13. The substrate according to claim 12, wherein said protective layer fixes a flow path forming member as resin construction through an organic adhesion promoting layer.
 14. The substrate according to claim 12, wherein said protective layer has an amorphous structure.
 15. The substrate according to claim 12, wherein said protective layer has a thickness within a range of 50 to 500 nm.
 16. An ink jet head comprising: a construction made by a resin for forming a discharge port for discharging ink, and an ink flow path communicated with said discharge port and having a portion effecting the ink with thermal energy for discharging ink; a base plate formed with a heat-generating resistor for generating energy for discharging ink; an electrode wiring provided on said base plate and electrically connected with said heat-generating resistor; and a protective layer provided above said heat-generating resistor and said electrode wiring, said protective layer being constituted of a two-layered section formed by a lower layer of a TaCr alloy and an upper layer of Ta, and of a single-layered section having said lower layer, wherein a resin construction made by resin is formed on said lower layer of said single-layered section and said upper layer of said two-layered section is provided at a position in contact with ink at least above said heat-generating resistor.
 17. The ink jet head according to claim 16, wherein said lower layer of said single-layered section fixes a flow path forming member as resin construction through an organic adhesion promoting layer.
 18. The ink jet head according to claim 16, wherein said lower layer of said protective layer contains Cr in an amount equal to or higher than 12 atomic %.
 19. The ink jet head according to claim 16, wherein said lower layer of said protective layer has an amorphous structure.
 20. The ink jet head according to claim 16, wherein said lower layer of said protective layer has a thickness within a range of 50 to 500 nm.
 21. The ink jet head according to claim 16, wherein said lower layer of said protective layer has a film stress which is at least a compression stress and is equal to or less than 1.0×10¹⁰ dyn/cm².
 22. An ink jet head comprising: a construction made by a resin for forming a discharge port for discharging ink, and an ink flow path communicated with said discharge port and having a portion effecting the ink with thermal energy for discharging ink; a base plate formed with a heat-generating resistor for generating energy for discharging ink; an electrode wiring provided on said base plate and electrically connected with said heat-generating resistor; and a protective layer provided above said heat-generating resistor and said electrode wiring, and constituted of a TaCr alloy containing Cr in an amount equal to or higher than 12 atomic %, a construction made by resin being formed on said protective layer.
 23. The ink jet head according to claim 22, wherein said protective layer fixes a flow path forming member as resin construction through an organic adhesion promoting layer.
 24. The ink jet head according to claim 22, wherein said protective layer has an amorphous structure.
 25. The ink jet head according to claim 22, wherein said protective layer has a thickness within a range of 50 to 500 nm.
 26. The ink jet head according to claim 22, wherein said protective layer has a film stress which is at least a compression stress and is equal to or less than 1.0×10¹⁰ dyn/cm².
 27. An ink jet head comprising: a construction made by a resin for forming a discharge port for discharging ink, and an ink flow path communicated with said discharge port and having a portion effecting the ink with thermal energy for discharging ink; a base plate formed with a heat-generating resistor for generating energy for discharging ink; an electrode wiring provided on said base plate and electrically connected with said heat-generating resistor; and a protective layer provided above said heat-generating resistor and said electrode wiring, and having a film stress which is at least a compression stress and is equal to or less than 1.0×10¹⁰ dyn/cm², a construction made by resin being formed on said protective layer.
 28. The ink jet head according to claim 27, wherein said protective layer fixes a flow path forming member as resin construction through an organic adhesion promoting layer.
 29. The ink jet head according to claim 27, wherein said protective layer has an amorphous structure.
 30. The ink jet head according to claim 27, wherein said protective layer has a thickness within a range of 50 to 500 nm.
 31. A producing method for an ink jet head including a construction made by a resin for forming a discharge port for discharging ink, and an ink flow path communicated with said discharge port and having a portion effecting the ink with thermal energy for discharging ink; a base plate formed with a heat-generating resistor for generating energy for discharging ink; an electrode wiring provided on said base plate and electrically connected with said heat-generating resistor; and a protective layer provided above said heat-generating resistor and said electrode wiring, said protective layer being constituted of a two-layered section formed by a lower layer of a TaCr alloy and an upper layer of Ta, and of a single-layered section having said lower layer, wherein a resin construction made by resin is formed on said lower layer of said single-layered section and said upper layer of said two-layered section is provided at a position in contact with ink at least above said heat-generating resistor, comprising the steps of: forming a protective layer in which a Ta layer is laminated on a layer formed by a TaCr alloy; selectively patterning said Ta layer and selectively removing said Ta layer; forming the ink flow path in a portion where the layer formed by said TaCr alloy is exposed by said removing.
 32. A producing method for an ink jet head including a construction made by a resin for forming a discharge port for discharging ink, and an ink flow path communicated with said discharge port and having a portion effecting the ink with thermal energy for discharging ink; a base plate formed with a heat-generating resistor for generating energy for discharging ink; an electrode wiring provided on said base plate and electrically connected with said heat-generating resistor; and a protective layer provided above said heat-generating resistor and said electrode wiring, and constituted of a TaCr alloy containing Cr in an amount equal to or higher than 12 atomic %, a construction made by resin being formed on said protective layer, comprising the steps of: forming a protective layer in which a Ta layer is laminated on a layer formed by a TaCr alloy; selectively patterning said Ta layer and selectively removing said Ta layer; forming the ink flow path in a portion where the layer formed by said TaCr alloy is exposed by said removing.
 33. A producing method for an ink jet head including a construction made by a resin for forming a discharge port for discharging ink, and an ink flow path communicated with said discharge port and having a portion effecting the ink with thermal energy for discharging ink; a base plate formed with a heat-generating resistor for generating energy for discharging ink; an electrode wiring provided on said base plate and electrically connected with said heat-generating resistor; and a protective layer provided above said heat-generating resistor and said electrode wiring, and having a film stress which is at least a compression stress and is equal to or less than 1.0×10¹⁰ dyn/cm², a construction made by resin being formed on said protective layer, comprising the steps of: forming a protective layer in which a Ta layer is laminated on a layer formed by a TaCr alloy; selectively patterning said Ta layer and selectively removing said Ta layer; forming the ink flow path in a portion where the layer formed by said TaCr alloy is exposed by said removing. 